1. Field of the Invention
The present invention relates generally to glucose monitoring sensors. More particularly, the present invention relates to glucose monitoring sensors and an inserter assembly therefor for continuous glucose monitoring in a patient.
2. Description of the Prior Art
Lancets are well-known devices commonly used in the medical field to make small punctures in a patient's skin in order to obtain samples of blood. They are utilized in hospitals, other medical facilities, and by private individuals such as diabetics for testing droplets of blood for various analytes. Typically, lancets are used only once in order to reduce the risk of HIV, hepatitis and other blood-borne diseases. The lancet or sharp of these devices is driven into the patient's skin by a small spring that is cocked by a technician or user prior to use. The lancet is covered with a protective, safety cap that keeps the end of the lancet sterile and is removed before use.
A variety of lancet devices are available for use by patients and/or healthcare practitioners. One lancet device is configured for multiple and/or repeated uses. In this variety, the user typically pushes a button or other device on a lancet injector to cause a lancet to penetrate the skin of a patient. More commonly, the lancet device effectively encases and fires the lancet into the patient's skin in order to puncture in an accurate, standardized and consistent manner. The lancet injector may also be provided with an adaptor cap to control and adjust the depth of penetration of the needle of the lancet.
Integrated lancet and sensor devices have been developed that combine the lancet and test strip or sensor into a single package. These integrated devices are typically used with a lancet injector where the integrated lancet and test strip is removed from the lancet injector and connected to a meter after acquisition by the test strip of the blood sample produced by the lancet, or used with a meter with built-in lancet injector.
More recently, continuous glucose monitoring devices have been developed for implanting into a patient's skin. Continuous monitoring systems typically use a tiny implantable sensor that is inserted under the skin, or into the subcutaneous fat layer to check analyte levels in the tissue fluid. A transmitter sends information about the analyte levels by way of, for example, a wire to a monitor or wirelessly by radio waves from the sensor to a wireless monitor. These devices are typically implanted for three to seven days of use to monitor in real-time a patient's glucose level.
One such device is disclosed in U.S. Pat. No. 5,299,571 to John Mastrototaro. The device is an apparatus for implantation of in-vivo sensors. The apparatus includes a housing, a dual-lumen tube extending therefrom, and an in-vivo sensor received within one of the lumens of the tube. A needle is received within the other lumen of the tube, and is used to insert the tube through the skin. After implantation, the needle is removed, and the flexible tube and sensor remain beneath the skin.
U.S. Patent Application Publication 2010/0022863 (2010, Mogensen et al.) discloses an inserter for a transcutaneous sensor. The inserter includes a needle unit and a sensor housing. The needle unit includes a needle hub and a carrier body. The sensor housing and the needle hub are releasably connected and when they are connected, the insertion needle is placed along the sensor (e.g. surrounding the sensor wholly or partly). The carrier body guides the movement relative to the housing between a retracted and an advanced position. When released, the needle unit and the sensor housing are forced by a spring unit to an advanced position where the needle and sensor are placed subcutaneously. Upwardly-bent parts on the leg of the housing set the insertion angle of about 30° into the skin of the patient.
U.S. Patent Application Publication 2012/0226122 (2012, Meuniot et al.) discloses an inserter device for an analyte sensor. The device includes a housing that is positioned above the subcutaneous fat layer, a blade shuttle, and a sensor shuttle. A spring is compressed between the blade shuttle and the sensor shuttle. The blade shuttle and sensor shuttle move towards the subcutaneous fat layer. When a spring force is released by the spring, the blade shuttle moves towards and pierces into the subcutaneous fat layer creating a pathway into the subcutaneous fat layer. The analyte sensor is implanted by the sensor shuttle by following the blade shuttle into the pathway created by the blade shuttle. The blade shuttle is then retracted from the subcutaneous fat layer, leaving the analyte sensor in the fat layer.
U.S. Patent Application Publication 2013/0256289 (2013, Hardvary et al.) discloses a diagnostic device. The diagnostic device has partially retractable hollow guide needles for the intradermal placement of diagnostic elements fixedly connected to measuring means within this device. This obviates the need to remove the guide needle and to connect the diagnostic elements to the measuring means after placement into the skin.